Sealing Your Ductwork? What Are You Using?

With a vibrant downtown, the Bengals, the Reds, the university and an exciting aquarium just across the river, Cincinnati is a terrific location. But the weather? Well, that can be all over the map — from hot and muggy, as it was last summer, to pretty darned chilly.

Keeping your home comfortable when temperatures are so extreme can get expensive. That’s why it’s smart to take energy-efficiency measures such as sealing your ductwork.

Compromised ductwork can cause you to lose as much as 20 percent of your conditioned air and lead to unwanted pressure imbalances. So it makes sense to shore up your ductwork, either as a DIY project or with the assistance of a qualified HVAC-system contractor. To do the job right, you need the right products, and in most cases that means mastic.

Using mastic Mastic is a white substance that feels like peanut butter or mayonnaise. Before you use it, make sure all connections are secured with No. 8 sheet-metal screws. Spread the mastic over the seams, using your fingers (wear gloves), a small brush or a putty knife. You can seal small tears this way, too. For larger gaps, you’ll also need mesh reinforcement. The job is messy — wear work clothes.

Why not duct tape? So are you surprised the job doesn’t call for duct tape? Truth is, standard cloth-backed duct tape isn’t heat resistant, and the adhesive won’t hold. As an alternative, some contractors use oriented polypropylene tape to secure the inner core of flex duct to metal collars. It’s a film-backed tape that has an acrylic adhesive that holds better than rubber adhesive. Some contractors are also using foil-backed butyl duct tape, which has a superior hold.

Although sealing ducts isn’t all that complicated, you may want to hire a professional to do the job. A professional can also discuss the advisability of insulating your ductwork.

To get the best advice about duct sealing or any other home-comfort issue, contact Apollo Home Heating, Cooling & Plumbing. Like you, we live in the Cincinnati area, and we’re committed to helping you realize energy savings throughout the year.